Single-particle energies in neutron-rich nuclei by shell model sum rule

摘要: One of the most striking features in neutron-rich nuclei is disappearance magic number $N=8$ or 20, which indicates a change single-particle energy spectra and large gap at number. A sum-rule method formulated, based on shell model, for evaluation energies. It shown that triplet-even central component $\mathit{NN}$ interaction plays decisive role through monopole spectra, leading to rapid decrease 20. The attraction due partly original second-order tensor correlations one-pion exchange potential. multipole expansion analysis interactions shows contribution from between two orbits depends nodal quantum numbers orbits.